1. Field of the Invention
The present invention relates to a pump apparatus for pumping, for example, fuel from a fuel tank on a vehicle to an engine mounted on the vehicle.
2. Brief Description of the Drawings
FIG. 1 is a longitudinal sectional view of a pump apparatus incorporating a pump of an embodiment of the invention;
FIG. 2 is a sectional view taken along the line II--II of FIG. 1;
FIG. 3 is a fragmentary side elevational view of an impeller incorporated in the pump shown in FIG. 1;
FIGS. 3A and 3B are sectional views taken along the lines IIIA--IIIA and IIIB--IIIB of FIG. 3, respectively;
FIG. 4 is a fragmentary enlarged sectional view of a pump incorporating the impeller shown in FIG. 3, illustrating particularly the state of flow of a fluid in the area around a third seal section of the pump;
FIG. 5 is a fragmentary side elevational view of a conventional impeller;
FIG. 5A is a sectional view taken along the line VA--VA of FIG. 5;
FIG. 6 is a fragmentary enlarged sectional view of a pump incorporating the impeller shown in FIG. 5, illustrating particularly the state of flow of a fluid around a third seal section of the pump;
FIGS. 7A and 7B are fragmentary sectional views of vane grooves in impellers employed in an experiments of comparing the performance of the pump of the present invention and of a conventional pump; and
FIGS. 8 and 9 are graphs illustrating the results of the experiments.